Freeze protection controller ETO2-4550

The control centre measures the outdoor temperature and, at the same time, detects the amount of ice and snow accumulated in the target area. The heating is only activated when temperature drops below the set value (0°C...+5°C) and when moisture is detected at the site. Once the snow and ice have melted and the melt water has drained away, the control unit deactivates the heating on the basis of the moisture readings. The heating is also deactivated when the temperature rises above set value.

The control centre can also be programmed to keep the heating activated for another 1–6 hours after the thawing has ended. An external timer can also be added to the control centre. It is also possble to switch the heating on manually for a desired period of time (0–6 h), in which case, the control ignores the sensor signals. The control centre is to be installed on a DIN-rail in, e.g., the electrical cabinet of the building.

In connection with the de-icing of outdoor areas and rainwater systems, the ground sensor ETOG-55 or ETOR-55 is to be embedded in the area that is to be kept free of ice and snow. The control can be made even more effective with the aid of the ETF-744 sensor that measures the outdoor temperature.

The ETO2 thermostat is used for controlling the melting of snow that has accumulated on, e.g., pavements, parking areas, loading bays, and gutters. The ETO measures both temperature and moisture, and it can be used for the controlling of heating cables and other heating products, as well. ETO is an effective de-icing control centre, and it is particularly suitable for the controlling of the ice and snow melting systems installed in vast outdoor areas and on extensive rainwater pipe systems. The thermostat contains two separate control circuits, which enables the simultaneous control of the de-icing of both the yard and the gutters. A load of up to 11 kW can be connected to the device. 

  • Three output relays (pot. vacant contact)
  • Control of solenoid valves with an external transformer (24 V AC, 6A) 
  • Integrated timer (1–6 h)
  • Two measurement settings (moisture and temperature/temperature)
Electrical number Product Name Pcs Buy
3530286 Freeze protection controller ETO2-4550
  • Nominal voltage: 230 V AC +/- 10%, 50/60 Hz
  • Three output relays (pot. vacant contact): 10 A, 10 A, 16 A
  • NOTE! Does not include any sensors (Select suitable sensors from our accessories)
  • On/off difference: 0.3°C
  • Temperature control range: -20°C...+10°C
  • Control range calibration with a potentiometer
  • Integrated timer for mechanical control
  • Ambient temperature: 0°C...+50°C
  • IP rating/with a surface-mounted enclosure: IP20/IP21
  • Dimensions (H x W x D): 90 x 156 x 45 mm


  •      ON: moisture and temperature
  •      OFF: temperature